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1da177e4 LT |
1 | /* |
2 | * X.25 Packet Layer release 002 | |
3 | * | |
4 | * This is ALPHA test software. This code may break your machine, | |
5 | * randomly fail to work with new releases, misbehave and/or generally | |
f8e1d201 | 6 | * screw up. It might even work. |
1da177e4 LT |
7 | * |
8 | * This code REQUIRES 2.1.15 or higher | |
9 | * | |
10 | * This module: | |
11 | * This module is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU General Public License | |
13 | * as published by the Free Software Foundation; either version | |
14 | * 2 of the License, or (at your option) any later version. | |
15 | * | |
16 | * History | |
17 | * X.25 001 Split from x25_subr.c | |
f8e1d201 | 18 | * mar/20/00 Daniela Squassoni Disabling/enabling of facilities |
1da177e4 | 19 | * negotiation. |
ebc3f64b SP |
20 | * apr/14/05 Shaun Pereira - Allow fast select with no restriction |
21 | * on response. | |
1da177e4 LT |
22 | */ |
23 | ||
24 | #include <linux/kernel.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/skbuff.h> | |
27 | #include <net/sock.h> | |
28 | #include <net/x25.h> | |
29 | ||
95c30430 | 30 | /** |
31 | * x25_parse_facilities - Parse facilities from skb into the facilities structs | |
32 | * | |
33 | * @skb: sk_buff to parse | |
25985edc | 34 | * @facilities: Regular facilities, updated as facilities are found |
95c30430 | 35 | * @dte_facs: ITU DTE facilities, updated as DTE facilities are found |
36 | * @vc_fac_mask: mask is updated with all facilities found | |
37 | * | |
38 | * Return codes: | |
39 | * -1 - Parsing error, caller should drop call and clean up | |
40 | * 0 - Parse OK, this skb has no facilities | |
41 | * >0 - Parse OK, returns the length of the facilities header | |
42 | * | |
1da177e4 | 43 | */ |
a64b7b93 SP |
44 | int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities, |
45 | struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask) | |
1da177e4 LT |
46 | { |
47 | unsigned char *p = skb->data; | |
f5eb917b | 48 | unsigned int len; |
1da177e4 LT |
49 | |
50 | *vc_fac_mask = 0; | |
51 | ||
a64b7b93 SP |
52 | /* |
53 | * The kernel knows which facilities were set on an incoming call but | |
54 | * currently this information is not available to userspace. Here we | |
55 | * give userspace who read incoming call facilities 0 length to indicate | |
56 | * it wasn't set. | |
57 | */ | |
58 | dte_facs->calling_len = 0; | |
59 | dte_facs->called_len = 0; | |
60 | memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae)); | |
61 | memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae)); | |
62 | ||
f5eb917b JH |
63 | if (skb->len < 1) |
64 | return 0; | |
65 | ||
66 | len = *p++; | |
67 | ||
68 | if (len >= skb->len) | |
69 | return -1; | |
70 | ||
1da177e4 LT |
71 | while (len > 0) { |
72 | switch (*p & X25_FAC_CLASS_MASK) { | |
73 | case X25_FAC_CLASS_A: | |
5ef41308 | 74 | if (len < 2) |
95c30430 | 75 | return -1; |
1da177e4 LT |
76 | switch (*p) { |
77 | case X25_FAC_REVERSE: | |
ebc3f64b SP |
78 | if((p[1] & 0x81) == 0x81) { |
79 | facilities->reverse = p[1] & 0x81; | |
80 | *vc_fac_mask |= X25_MASK_REVERSE; | |
81 | break; | |
82 | } | |
83 | ||
84 | if((p[1] & 0x01) == 0x01) { | |
85 | facilities->reverse = p[1] & 0x01; | |
86 | *vc_fac_mask |= X25_MASK_REVERSE; | |
87 | break; | |
88 | } | |
89 | ||
90 | if((p[1] & 0x80) == 0x80) { | |
91 | facilities->reverse = p[1] & 0x80; | |
92 | *vc_fac_mask |= X25_MASK_REVERSE; | |
93 | break; | |
94 | } | |
95 | ||
96 | if(p[1] == 0x00) { | |
97 | facilities->reverse | |
98 | = X25_DEFAULT_REVERSE; | |
99 | *vc_fac_mask |= X25_MASK_REVERSE; | |
100 | break; | |
101 | } | |
102 | ||
1da177e4 LT |
103 | case X25_FAC_THROUGHPUT: |
104 | facilities->throughput = p[1]; | |
105 | *vc_fac_mask |= X25_MASK_THROUGHPUT; | |
106 | break; | |
a64b7b93 SP |
107 | case X25_MARKER: |
108 | break; | |
1da177e4 LT |
109 | default: |
110 | printk(KERN_DEBUG "X.25: unknown facility " | |
111 | "%02X, value %02X\n", | |
112 | p[0], p[1]); | |
113 | break; | |
114 | } | |
115 | p += 2; | |
116 | len -= 2; | |
117 | break; | |
118 | case X25_FAC_CLASS_B: | |
5ef41308 | 119 | if (len < 3) |
95c30430 | 120 | return -1; |
1da177e4 LT |
121 | switch (*p) { |
122 | case X25_FAC_PACKET_SIZE: | |
123 | facilities->pacsize_in = p[1]; | |
124 | facilities->pacsize_out = p[2]; | |
125 | *vc_fac_mask |= X25_MASK_PACKET_SIZE; | |
126 | break; | |
127 | case X25_FAC_WINDOW_SIZE: | |
128 | facilities->winsize_in = p[1]; | |
129 | facilities->winsize_out = p[2]; | |
130 | *vc_fac_mask |= X25_MASK_WINDOW_SIZE; | |
131 | break; | |
132 | default: | |
133 | printk(KERN_DEBUG "X.25: unknown facility " | |
134 | "%02X, values %02X, %02X\n", | |
135 | p[0], p[1], p[2]); | |
136 | break; | |
137 | } | |
138 | p += 3; | |
139 | len -= 3; | |
140 | break; | |
141 | case X25_FAC_CLASS_C: | |
5ef41308 | 142 | if (len < 4) |
95c30430 | 143 | return -1; |
1da177e4 LT |
144 | printk(KERN_DEBUG "X.25: unknown facility %02X, " |
145 | "values %02X, %02X, %02X\n", | |
146 | p[0], p[1], p[2], p[3]); | |
147 | p += 4; | |
148 | len -= 4; | |
149 | break; | |
150 | case X25_FAC_CLASS_D: | |
5ef41308 | 151 | if (len < p[1] + 2) |
95c30430 | 152 | return -1; |
a64b7b93 | 153 | switch (*p) { |
f8e1d201 | 154 | case X25_FAC_CALLING_AE: |
a6331d6f | 155 | if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1) |
95c30430 | 156 | return -1; |
a64b7b93 SP |
157 | dte_facs->calling_len = p[2]; |
158 | memcpy(dte_facs->calling_ae, &p[3], p[1] - 1); | |
159 | *vc_fac_mask |= X25_MASK_CALLING_AE; | |
160 | break; | |
161 | case X25_FAC_CALLED_AE: | |
a6331d6f | 162 | if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1) |
95c30430 | 163 | return -1; |
a64b7b93 SP |
164 | dte_facs->called_len = p[2]; |
165 | memcpy(dte_facs->called_ae, &p[3], p[1] - 1); | |
166 | *vc_fac_mask |= X25_MASK_CALLED_AE; | |
167 | break; | |
168 | default: | |
169 | printk(KERN_DEBUG "X.25: unknown facility %02X," | |
5ef41308 | 170 | "length %d\n", p[0], p[1]); |
a64b7b93 SP |
171 | break; |
172 | } | |
1da177e4 | 173 | len -= p[1] + 2; |
a64b7b93 | 174 | p += p[1] + 2; |
1da177e4 LT |
175 | break; |
176 | } | |
177 | } | |
178 | ||
179 | return p - skb->data; | |
180 | } | |
181 | ||
182 | /* | |
183 | * Create a set of facilities. | |
184 | */ | |
185 | int x25_create_facilities(unsigned char *buffer, | |
a64b7b93 SP |
186 | struct x25_facilities *facilities, |
187 | struct x25_dte_facilities *dte_facs, unsigned long facil_mask) | |
1da177e4 LT |
188 | { |
189 | unsigned char *p = buffer + 1; | |
190 | int len; | |
191 | ||
192 | if (!facil_mask) { | |
193 | /* | |
194 | * Length of the facilities field in call_req or | |
195 | * call_accept packets | |
196 | */ | |
197 | buffer[0] = 0; | |
198 | len = 1; /* 1 byte for the length field */ | |
199 | return len; | |
200 | } | |
201 | ||
202 | if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) { | |
203 | *p++ = X25_FAC_REVERSE; | |
ebc3f64b | 204 | *p++ = facilities->reverse; |
1da177e4 LT |
205 | } |
206 | ||
207 | if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) { | |
208 | *p++ = X25_FAC_THROUGHPUT; | |
209 | *p++ = facilities->throughput; | |
210 | } | |
211 | ||
212 | if ((facilities->pacsize_in || facilities->pacsize_out) && | |
213 | (facil_mask & X25_MASK_PACKET_SIZE)) { | |
214 | *p++ = X25_FAC_PACKET_SIZE; | |
215 | *p++ = facilities->pacsize_in ? : facilities->pacsize_out; | |
216 | *p++ = facilities->pacsize_out ? : facilities->pacsize_in; | |
217 | } | |
218 | ||
219 | if ((facilities->winsize_in || facilities->winsize_out) && | |
220 | (facil_mask & X25_MASK_WINDOW_SIZE)) { | |
221 | *p++ = X25_FAC_WINDOW_SIZE; | |
222 | *p++ = facilities->winsize_in ? : facilities->winsize_out; | |
223 | *p++ = facilities->winsize_out ? : facilities->winsize_in; | |
224 | } | |
225 | ||
a64b7b93 SP |
226 | if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) { |
227 | *p++ = X25_MARKER; | |
228 | *p++ = X25_DTE_SERVICES; | |
229 | } | |
230 | ||
231 | if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) { | |
6bf1574e | 232 | unsigned bytecount = (dte_facs->calling_len + 1) >> 1; |
a64b7b93 SP |
233 | *p++ = X25_FAC_CALLING_AE; |
234 | *p++ = 1 + bytecount; | |
235 | *p++ = dte_facs->calling_len; | |
236 | memcpy(p, dte_facs->calling_ae, bytecount); | |
237 | p += bytecount; | |
238 | } | |
239 | ||
240 | if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) { | |
241 | unsigned bytecount = (dte_facs->called_len % 2) ? | |
242 | dte_facs->called_len / 2 + 1 : | |
243 | dte_facs->called_len / 2; | |
244 | *p++ = X25_FAC_CALLED_AE; | |
245 | *p++ = 1 + bytecount; | |
246 | *p++ = dte_facs->called_len; | |
247 | memcpy(p, dte_facs->called_ae, bytecount); | |
248 | p+=bytecount; | |
249 | } | |
250 | ||
1da177e4 LT |
251 | len = p - buffer; |
252 | buffer[0] = len - 1; | |
253 | ||
254 | return len; | |
255 | } | |
256 | ||
257 | /* | |
258 | * Try to reach a compromise on a set of facilities. | |
259 | * | |
260 | * The only real problem is with reverse charging. | |
261 | */ | |
262 | int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk, | |
a64b7b93 | 263 | struct x25_facilities *new, struct x25_dte_facilities *dte) |
1da177e4 LT |
264 | { |
265 | struct x25_sock *x25 = x25_sk(sk); | |
266 | struct x25_facilities *ours = &x25->facilities; | |
267 | struct x25_facilities theirs; | |
268 | int len; | |
269 | ||
270 | memset(&theirs, 0, sizeof(theirs)); | |
271 | memcpy(new, ours, sizeof(*new)); | |
272 | ||
a64b7b93 | 273 | len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask); |
f5eb917b JH |
274 | if (len < 0) |
275 | return len; | |
1da177e4 LT |
276 | |
277 | /* | |
278 | * They want reverse charging, we won't accept it. | |
279 | */ | |
ebc3f64b | 280 | if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) { |
d2e7543c | 281 | SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n"); |
1da177e4 LT |
282 | return -1; |
283 | } | |
284 | ||
285 | new->reverse = theirs.reverse; | |
286 | ||
287 | if (theirs.throughput) { | |
ddd0451f JH |
288 | int theirs_in = theirs.throughput & 0x0f; |
289 | int theirs_out = theirs.throughput & 0xf0; | |
290 | int ours_in = ours->throughput & 0x0f; | |
291 | int ours_out = ours->throughput & 0xf0; | |
292 | if (!ours_in || theirs_in < ours_in) { | |
293 | SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n"); | |
294 | new->throughput = (new->throughput & 0xf0) | theirs_in; | |
295 | } | |
296 | if (!ours_out || theirs_out < ours_out) { | |
297 | SOCK_DEBUG(sk, | |
298 | "X.25: outbound throughput negotiated\n"); | |
299 | new->throughput = (new->throughput & 0x0f) | theirs_out; | |
1da177e4 LT |
300 | } |
301 | } | |
302 | ||
303 | if (theirs.pacsize_in && theirs.pacsize_out) { | |
304 | if (theirs.pacsize_in < ours->pacsize_in) { | |
d2e7543c | 305 | SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n"); |
1da177e4 LT |
306 | new->pacsize_in = theirs.pacsize_in; |
307 | } | |
308 | if (theirs.pacsize_out < ours->pacsize_out) { | |
d2e7543c | 309 | SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n"); |
1da177e4 LT |
310 | new->pacsize_out = theirs.pacsize_out; |
311 | } | |
312 | } | |
313 | ||
314 | if (theirs.winsize_in && theirs.winsize_out) { | |
315 | if (theirs.winsize_in < ours->winsize_in) { | |
d2e7543c | 316 | SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n"); |
1da177e4 LT |
317 | new->winsize_in = theirs.winsize_in; |
318 | } | |
319 | if (theirs.winsize_out < ours->winsize_out) { | |
d2e7543c | 320 | SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n"); |
1da177e4 LT |
321 | new->winsize_out = theirs.winsize_out; |
322 | } | |
323 | } | |
324 | ||
325 | return len; | |
326 | } | |
327 | ||
328 | /* | |
f8e1d201 | 329 | * Limit values of certain facilities according to the capability of the |
1da177e4 LT |
330 | * currently attached x25 link. |
331 | */ | |
332 | void x25_limit_facilities(struct x25_facilities *facilities, | |
333 | struct x25_neigh *nb) | |
334 | { | |
335 | ||
336 | if (!nb->extended) { | |
337 | if (facilities->winsize_in > 7) { | |
338 | printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n"); | |
339 | facilities->winsize_in = 7; | |
340 | } | |
341 | if (facilities->winsize_out > 7) { | |
342 | facilities->winsize_out = 7; | |
343 | printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n"); | |
344 | } | |
345 | } | |
346 | } |